Control of breathing using an extracorporeal membrane lung

Area of Science:

• Cardiopulmonary physiology
• Respiratory support technologies
• Neonatal and pediatric critical care

Background:

• Spontaneously breathing lambs underwent extracorporeal membrane oxygenation (ECMO) with varying CO2 removal rates.
• Understanding the relationship between extracorporeal CO2 removal and native respiratory drive is crucial for optimizing ECMO support.
• Previous research has explored ECMO's efficacy, but precise control of ventilation via CO2 removal requires further elucidation.

Purpose of the Study:

• To investigate the impact of different extracorporeal carbon dioxide removal (ECCO2R) levels on alveolar ventilation in spontaneously breathing lambs.
• To determine the feasibility of controlling pulmonary ventilation through mechanical CO2 removal.
• To establish the relationship between the fraction of CO2 removed and the resultant decrease in alveolar ventilation.

Main Methods:

• Lambs were connected to an extracorporeal membrane lung circuit.
• Carbon dioxide removal was modulated through adjustments to the membrane lung settings.
• Alveolar ventilation was measured and correlated with the extracorporeal CO2 removal fraction.
• Carbon dioxide production (VCO2) was used as a benchmark for CO2 removal.

Main Results:

• A direct proportionality was observed between the decrease in alveolar ventilation and the fraction of total CO2 removed by the membrane lung.
• As extracorporeal CO2 removal approached the lamb's endogenous CO2 production (VCO2), alveolar ventilation diminished significantly, nearing cessation.
• The study demonstrated a graded response of alveolar ventilation to varying levels of ECCO2R.

Conclusions:

• Extracorporeal carbon dioxide removal is an effective method for controlling pulmonary ventilation in spontaneously breathing subjects.
• ECCO2R can be precisely modulated to achieve desired levels of respiratory support, offering a potential alternative or adjunct to conventional mechanical ventilation.
• This technique holds promise for managing respiratory failure, particularly in neonatal and pediatric populations where lung protective strategies are paramount.